The present invention relates to a novel compression sleeve for use in per se known systems for applying compressive pressure to a patient's leg. Prior to the present invention, various compression devices have been known in the art for applying compressive pressure to a patient's limbs in order to increase blood flow velocity. Particularly useful are the SCD (trademark of The Kendall Company, assignee of the present invention) sequential compression devices providing intermittent pulses of compressed air which sequentially inflate multiple chambers in a sleeve, beginning at the ankle and moving up the leg. This results in a wave-like milking action which empties the veins and results in greatly increased peak blood flow velocity, thus providing a non-invasive method of prophylaxis to reduce the incidence of deep vein thrombosis (DVT). These compression devices find particular use during surgery on patients with high risk conditions such as obesity, advanced age, malignancy, or prior thromboembolism. When a DVT occurs, the valves that are located within the veins of the legs can be damaged, which in turn can cause stasis and high pressure in the veins of the lower leg. Patients who have this condition often have swelling (edema) and tissue breakdown (venous stasis ulcer) in the lower leg.
Devices of the foregoing description are disclosed in various patents of which the following are illustrative: U.S. Pat. Nos. 4,013,069 and 4,030,488 of James H. Hasty, and U.S. Pat. No. 4,029,087 of, John F. Dye, all assigned to The Kendall Company.
As examples of other patents directed to compression sleeves for use in these systems, mention may be made of the following: U.S. Pat. Nos. 4,091,804; 4,156,425; 4,198 961; and 4,207,875
In general, the compression devices of the prior art comprise a sleeve having a plurality of separate fluid pressure chambers progressively arranged longitudinally along the sleeve from a lower portion of the limb to an upper portion. Means are provided for intermittently forming a pressure pulse within these chambers from a source of pressurized fluid during periodic compression cycles. Preferably, the sleeve provides a compressive pressure gradient against the patient's limbs during these compression cycles which progressively decreases from the lower portion of the limb, e.g. from the ankle to the thigh.
sequential pneumatic compression devices of the foregoing description applying compression to the lower limb have achieved considerable notoriety and wide acceptance as an effective non-invasive means for preventing deep vein thrombosis and for treating venous stasis ulcers.
They function by applying pneumatic compression sequentially and in gradient levels from ankle to thigh for a predetermined time, e.g. 11 seconds, followed by a period of time, e.g. 60 seconds, when no pressure is applied. The particular time period selected is chosen to be optimum for pushing venous blood out of the leg (during the compression cycle) and to allow arterial blood to refill the leg (during the decompression interval).
While the compression devices of the prior art for applying compressive pressure to the leg have enjoyed great commercial success and the clinical efficacy of the SCD devices in particular have been well documented, there nevertheless remains a need in the art for a sleeve of improved design for facilitating proper placement on the leg and for increased comfort to the patient wearing the sleeve.
stated simply, the task of this invention is to provide such an improved sleeve design.
These compression sleeves usually use hook and loop type fasteners to fasten one part of the compression sleeve to the other when it is placed on a patient. The hook and loop type fasteners are commonly known by the trademark VELCRO. Typically, the fasteners are attached to the compression sleeve by sewing. This has become unacceptable, however because sewing does not tend to lend itself to automation.
A better method was then used. This method uses a type of VELCRO fastener that can be RF welded to the sleeve rather than sewn. RF welding is known and described in patents such as U.S. Pat. No. 4,857,129, to Jensen, et al. This method solves many of the problems outlined above.
Finally, the instant improvement to the compression sleeves concerns how the loop portion of the VELCRO fastener is RF welded to its sheet of the compression sleeve. As shown in FIGS. 9A-9E, according to the prior art, a fairly complicated five-step process was used. First (FIG. 9A), the 12 mil vinyl strip portions 100 were cut to the appropriate size. These vinyl strip portions have slits 101 at opposite ends thereof to facilitate the removal of a "window" of vinyl, as will be described. Second (FIG. 9B), the loop portions 56 were cut to their appropriate size. Third (FIG. 9C), the loops 56 were welded 106 to the vinyl strip 100 to form a sub-assembly 105. This step was carried out in such a way that the vinyl strip 100 covered the loops 56, yet exposed the foam underside of the loop portion 56. Accordingly, this vinyl strip 100 was not a "backing" because it covered the front of loop portion 56. Fourth (FIG. 9D), this sub-assembly was reversed and the vinyl strip portion 100 of the subassembly was RF welded 107 to the sheet 30 of the compression sleeve with the foam underside portion contacting the sheet of the compression sleeve. Fifth (FIG. 9E) and finally, a "window" 100a of the vinyl strip 100 was removed to expose the loop structure after attachment. Slits 101 allowed for there to be a portion of the vinyl strip 100 which could be grasped for removal of the "window." This final step does not lend itself to automation and the overall process is quite cumbersome. Therefore, a method by which the loop portion could be directly bonded to the sheet of the sleeve was needed.
The prior art has not found such a method. For example, U.S. Pat. No. 4,643,932, to Daniels, generically recites that it is known to ultrasonically weld VELCRO to an article. He lacks any explicit description, however, on how this is accomplished by the prior art. When describing his invention, he does state that a heat activated adhesive film is used to bond the VELCRO portion to its backing, i.e., the article.
U.S. Pat. No. 4,894,060, to Nestegard broadly discusses a bonding layer for attaching his loop portion to the diaper, yet fails to describe any details, thereof.
U.S. Pat. No. 4,761,318, to Ott, et al., uses an infrared source in combination with pressing rollers to attach the loop portion to the substrate. This method, besides not showing some of the details of the instant claimed method, fails to allow discrete strips of loop material to be attached to discrete substrate materials, as does the instant invention.
other methods of attaching VELCRO to an article or substrate are shown in U.S. Pat. No. 5,061,540, to Cripps, et al. (fails to describe the details of how the VELCRO can be ultra-sonically welded to the article); U.S. Pat. No. 5,095,894, to marble (loop portion flame laminated to article); U.S. Pat. No. 4,470,857, to Casalou (first a barrier sheet is bonded to the substrate and then the VELCRO bonded to the barrier sheet); PCT/USA85/02290, to VELCRO USA (ultrasonically welding VELCRO to a substrate, and then attaching the substrate/VELCRO combination to the article as the article is molded, by encapsulating the substrate. Finally, U.S. Pat. No. 4,662,037, to Provost, et al., discloses the use of ultrasonic welding in order to create a selvedge (selvage). Furthermore, many of the above-mentioned patents use ultra-sonic rather than RF welding. These are distinctly different types of welding and RF welding is more suitable for welding PVC, the material that the compression sleeves are made from. RF welding uses radio frequency radiation (usually 27.12 Mhz) to induce molecular friction in the material to be welded, raising the temperature to its melting point. RF welding is useful for sealing polymers with strong dipoles, such as PVC.